Fixes:
------

- Fix a regression in 3.5.5 when checking for execute permissions in
  execve(2) and access(2).
  Addresses: https://cygwin.com/pipermail/cygwin/2024-December/256972.html

- Fix a regression since 3.5.0 which fails to use POSIX semantics in
  unlink/rename on NTFS.

- Add fd validation where needed in mq_* functions.
  Addresses: https://cygwin.com/pipermail/cygwin/2025-January/257090.html

- Fix regression in 3.5.5 which causes process hangs.
  Addresses: https://cygwin.com/pipermail/cygwin/2024-December/256954.html
  Addresses: https://cygwin.com/pipermail/cygwin/2024-December/256971.html
  Addresses: https://cygwin.com/pipermail/cygwin/2025-January/257058.html
  Addresses: https://cygwin.com/pipermail/cygwin/2024-December/256987.html

- Minor updates to load average calculations.
  Addresses: https://cygwin.com/pipermail/cygwin/2024-August/256361.html

- Fix mq_unlink().
  Addresses: https://cygwin.com/pipermail/cygwin/2025-January/257119.html
